Ravens sign center Casey Rabach (updated with Birk injury issue)

With starting center Matt Birk battling knee injuries and getting up there in age, the Ravens added insurance to the middle of their offensive line today, signing veteran center Casey Rabach to a two-year contract.

This is Rabach’s second stint with the Ravens; he was originally drafted by Baltimore in the third round in 2001. He played four seasons for the Ravens and started every game during the 2004 season.

Rabach has spent the last six seasons with the Redskins, and he was a workhorse during that time, starting all but one game. He has 118 starts in his career.

The 33-year-old Wisconsin product stands at 6-foot-4, 288-lbs., and will improve the Ravens’ depth not only at center, but also at both guard spots. Chris Chester, who had served as the team’s backup center and guard, signed with the Redskins last week.

UPDATE: ESPN is reporting that Birk may need arthroscopic surgery on his injured left knee, which has been wrapped. Birk watched yesterday’s practice from the sidelines, and he is not on the field at all today.

Rabach’s signing could indicate that the Ravens are worried about the possibility of Birk being able to go this season.